All anticipatory performance questions require a solid grasp of response-time analysis, which is the first topic of this chapter. The good news is that if you have a solid understanding of the topics covered in the first few chapters, you are adequately prepared. (If you just opened this book, I highly recommend you review those first few chapters, as they set the foundation for this chapter.) Next, I'll present a fundamental and surprisingly flexible concept commonly called utilization. Response-time analysis combined with a solid grasp of utilization will prepare you for the next topic, which is understanding the various ways our solutions influence performance. Finally, we'll dive into anticipating our solution's impact in terms of time and utilization. To ensure you can do everything presented in this chapter, I will provide a number of examples. That's a tall order for a single chapter, so let's get started!

Oracle performance analysis that is fundamentally based on response-time analysis has the inherent advantage of naturally being expanded into anticipating change. To do this, we need to take the components of response time another level deeper, reduce some of the abstraction I have been using in this book, and examine the relationship between response-time components specifically used in an Oracle environment.

When rivers flow into the ocean, people enter an elevator, and transactions enter an Oracle system, over an interval of time, they arrive at an average rate. It could be that just before Friday's time card entry deadline between 4:30 p.m. and 5:00 p.m, 9,000 transactions occurred.